[gssapi-openssh.git] / openssh / auth2-gss.c

/*
 * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "includes.h"

#ifdef GSSAPI
#include "auth.h"
#include "ssh2.h"
#include "xmalloc.h"
#include "log.h"
#include "dispatch.h"
#include "servconf.h"
#include "compat.h"
#include "packet.h"
#include "monitor_wrap.h"

#include "ssh-gss.h"

extern ServerOptions options;

static int
userauth_external(Authctxt *authctxt)
{
        packet_check_eom();

        return(PRIVSEP(ssh_gssapi_userok(authctxt->user)));
}

static void ssh_gssapi_userauth_error(Gssctxt *ctxt);
static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
static void input_gssapi_errtok(int, u_int32_t, void *);

/* We only support those mechanisms that we know about (ie ones that we know
 * how to check local user kuserok and the like
 */
static int
userauth_gssapi(Authctxt *authctxt)
{
        gss_OID_desc    oid= {0,NULL};
        Gssctxt         *ctxt = NULL;
        int             mechs;
        gss_OID_set     supported;
        int             present;
        OM_uint32       ms;
        u_int           len;
        char *		doid = NULL;
        
        if (!authctxt->valid || authctxt->user == NULL)
                return 0;
                
        if (datafellows & SSH_OLD_GSSAPI) {
                debug("Early drafts of GSSAPI userauth not supported");
                return 0;
        }
        
        mechs=packet_get_int();
        if (mechs==0) {
                debug("Mechanism negotiation is not supported");
                return 0;
        }

        ssh_gssapi_supported_oids(&supported);
        do {
                mechs--;
                
                if (doid)
                        xfree(doid);
                
                debug("Trying to get OID string");
                doid = packet_get_string(&len);
                debug("Got string");
                
               	if (doid[0]!=0x06 || doid[1]!=len-2) {
               		log("Mechanism OID received using the old encoding form");
               		oid.elements = doid;
               		oid.length = len;
               	} else {
               		oid.elements = doid + 2;
               		oid.length   = len - 2;
               	}
            	gss_test_oid_set_member(&ms, &oid, supported, &present);
        } while (mechs>0 && !present);
        
        if (!present) {
                xfree(doid);
                return(0);
        }
                
	if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt,&oid)))) {
		ssh_gssapi_userauth_error(ctxt);
		return(0);
	}
	
        authctxt->methoddata=(void *)ctxt;

        /* Send SSH_MSG_USERAUTH_GSSAPI_RESPONSE */

       	packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);

	/* Just return whatever they sent */
	packet_put_string(doid,len);
       	
        packet_send();
        packet_write_wait();
        xfree(doid);

        dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, 
                     &input_gssapi_token);
        dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK,
        	     &input_gssapi_errtok);
        authctxt->postponed = 1;
        
        return 0;
}

static void
input_gssapi_token(int type, u_int32_t plen, void *ctxt)
{
        Authctxt *authctxt = ctxt;
        Gssctxt *gssctxt;
        gss_buffer_desc send_tok,recv_tok;
        OM_uint32 maj_status, min_status;
        
        if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
                fatal("No authentication or GSSAPI context");
                
        gssctxt=authctxt->methoddata;
        recv_tok.value=packet_get_string(&recv_tok.length);
        
        maj_status=PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok, 
        					 &send_tok, NULL));
        packet_check_eom();
        
        if (GSS_ERROR(maj_status)) {
        	ssh_gssapi_userauth_error(gssctxt);
		if (send_tok.length != 0) {
			packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
	                packet_put_string(send_tok.value,send_tok.length);
        	        packet_send();
               		packet_write_wait();
               	}
                authctxt->postponed = 0;
                dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
                userauth_finish(authctxt, 0, "gssapi");
        } else {
               	if (send_tok.length != 0) {
               		packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
               		packet_put_string(send_tok.value,send_tok.length);
               		packet_send();
               		packet_write_wait();
                }
	        if (maj_status == GSS_S_COMPLETE) {
        	        dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,NULL);
                	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
                             	     &input_gssapi_exchange_complete);
                }
        }
        
        gss_release_buffer(&min_status, &send_tok);        
}

static void
input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
{
        Authctxt *authctxt = ctxt;
        Gssctxt *gssctxt;
        gss_buffer_desc send_tok,recv_tok;
        OM_uint32 maj_status;
        
        if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
                fatal("No authentication or GSSAPI context");
                
        gssctxt=authctxt->methoddata;
        recv_tok.value=packet_get_string(&recv_tok.length);
        
        /* Push the error token into GSSAPI to see what it says */
        maj_status=PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok, 
        					 &send_tok, NULL));
        packet_check_eom();

	/* We can't return anything to the client, even if we wanted to */
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK,NULL);

	/* The client will have already moved on to the next auth */
	
}

/* This is called when the client thinks we've completed authentication.
 * It should only be enabled in the dispatch handler by the function above,
 * which only enables it once the GSSAPI exchange is complete.
 */
 
static void
input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
{
        Authctxt *authctxt = ctxt;
        Gssctxt *gssctxt;
        int authenticated;
        
	if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
                fatal("No authentication or GSSAPI context");
                
        gssctxt=authctxt->methoddata;
        
	/* We don't need to check the status, because the stored credentials
	 * which userok uses are only populated once the context init step
	 * has returned complete.
	 */

        authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));

        authctxt->postponed = 0;
        dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
        dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
        dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
        userauth_finish(authctxt, authenticated, "gssapi");
}

static void ssh_gssapi_userauth_error(Gssctxt *ctxt) {
	char *errstr;
	OM_uint32 maj,min;
	
	errstr=PRIVSEP(ssh_gssapi_last_error(ctxt,&maj,&min));
	if (errstr) {
		packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERROR);
		packet_put_int(maj);
		packet_put_int(min);
		packet_put_cstring(errstr);
		packet_put_cstring("");
		packet_send();
		packet_write_wait();
		xfree(errstr);
	}
}

Authmethod method_external = {
	"external-keyx",
	userauth_external,
	&options.gss_authentication
};
	
Authmethod method_gssapi = {
        "gssapi",
        userauth_gssapi,
        &options.gss_authentication
};

#endif /* GSSAPI */
Commit	Line	Data
73b00670	1	/*
	2	* Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
	3	*
	4	* Redistribution and use in source and binary forms, with or without
	5	* modification, are permitted provided that the following conditions
	6	* are met:
	7	* 1. Redistributions of source code must retain the above copyright
	8	* notice, this list of conditions and the following disclaimer.
	9	* 2. Redistributions in binary form must reproduce the above copyright
	10	* notice, this list of conditions and the following disclaimer in the
	11	* documentation and/or other materials provided with the distribution.
	12	*
	13	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AS IS'' AND ANY EXPRESS OR
	14	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	15	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	16	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	17	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	18	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	19	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	20	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	21	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	22	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	23	*/
	24
	25	#include "includes.h"
	26
	27	#ifdef GSSAPI
	28	#include "auth.h"
	29	#include "ssh2.h"
	30	#include "xmalloc.h"
	31	#include "log.h"
	32	#include "dispatch.h"
	33	#include "servconf.h"
	34	#include "compat.h"
	35	#include "packet.h"
	36	#include "monitor_wrap.h"
	37
	38	#include "ssh-gss.h"
	39
	40	extern ServerOptions options;
	41
	42	static int
	43	userauth_external(Authctxt *authctxt)
	44	{
	45	packet_check_eom();
	46
	47	return(PRIVSEP(ssh_gssapi_userok(authctxt->user)));
	48	}
	49
	50	static void ssh_gssapi_userauth_error(Gssctxt *ctxt);
	51	static void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
	52	static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt);
3e196425	53	static void input_gssapi_errtok(int, u_int32_t, void *);
73b00670	54
	55	/* We only support those mechanisms that we know about (ie ones that we know
	56	* how to check local user kuserok and the like
	57	*/
	58	static int
	59	userauth_gssapi(Authctxt *authctxt)
	60	{
	61	gss_OID_desc oid= {0,NULL};
	62	Gssctxt *ctxt = NULL;
	63	int mechs;
	64	gss_OID_set supported;
	65	int present;
	66	OM_uint32 ms;
	67	u_int len;
	68	char * doid = NULL;
	69
	70	if (!authctxt->valid \|\| authctxt->user == NULL)
	71	return 0;
	72
	73	if (datafellows & SSH_OLD_GSSAPI) {
	74	debug("Early drafts of GSSAPI userauth not supported");
	75	return 0;
	76	}
	77
	78	mechs=packet_get_int();
	79	if (mechs==0) {
	80	debug("Mechanism negotiation is not supported");
	81	return 0;
	82	}
	83
	84	ssh_gssapi_supported_oids(&supported);
	85	do {
	86	mechs--;
	87
	88	if (doid)
	89	xfree(doid);
	90
	91	debug("Trying to get OID string");
	92	doid = packet_get_string(&len);
	93	debug("Got string");
	94
3e196425	95	if (doid[0]!=0x06 \|\| doid[1]!=len-2) {
	96	log("Mechanism OID received using the old encoding form");
	97	oid.elements = doid;
	98	oid.length = len;
	99	} else {
	100	oid.elements = doid + 2;
	101	oid.length = len - 2;
	102	}
	103	gss_test_oid_set_member(&ms, &oid, supported, &present);
73b00670	104	} while (mechs>0 && !present);
	105
	106	if (!present) {
	107	xfree(doid);
	108	return(0);
	109	}
	110
	111	if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt,&oid)))) {
	112	ssh_gssapi_userauth_error(ctxt);
	113	return(0);
	114	}
	115
	116	authctxt->methoddata=(void *)ctxt;
	117
	118	/* Send SSH_MSG_USERAUTH_GSSAPI_RESPONSE */
	119
	120	packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE);
	121
3e196425	122	/* Just return whatever they sent */
3e196425	123	packet_put_string(doid,len);
73b00670	124
	125	packet_send();
	126	packet_write_wait();
	127	xfree(doid);
	128
	129	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,
	130	&input_gssapi_token);
3e196425	131	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK,
3e196425	132	&input_gssapi_errtok);
73b00670	133	authctxt->postponed = 1;
	134
	135	return 0;
	136	}
	137
	138	static void
	139	input_gssapi_token(int type, u_int32_t plen, void *ctxt)
	140	{
	141	Authctxt *authctxt = ctxt;
	142	Gssctxt *gssctxt;
	143	gss_buffer_desc send_tok,recv_tok;
	144	OM_uint32 maj_status, min_status;
	145
	146	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	147	fatal("No authentication or GSSAPI context");
	148
	149	gssctxt=authctxt->methoddata;
	150	recv_tok.value=packet_get_string(&recv_tok.length);
	151
	152	maj_status=PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
3e196425	153	&send_tok, NULL));
73b00670	154	packet_check_eom();
3e196425	155
73b00670	156	if (GSS_ERROR(maj_status)) {
3e196425	157	ssh_gssapi_userauth_error(gssctxt);
	158	if (send_tok.length != 0) {
	159	packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
	160	packet_put_string(send_tok.value,send_tok.length);
	161	packet_send();
	162	packet_write_wait();
	163	}
73b00670	164	authctxt->postponed = 0;
	165	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	166	userauth_finish(authctxt, 0, "gssapi");
3e196425	167	} else {
	168	if (send_tok.length != 0) {
	169	packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
	170	packet_put_string(send_tok.value,send_tok.length);
	171	packet_send();
	172	packet_write_wait();
	173	}
	174	if (maj_status == GSS_S_COMPLETE) {
	175	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,NULL);
	176	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
	177	&input_gssapi_exchange_complete);
	178	}
73b00670	179	}
3e196425	180
	181	gss_release_buffer(&min_status, &send_tok);
	182	}
73b00670	183
3e196425	184	static void
	185	input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
	186	{
	187	Authctxt *authctxt = ctxt;
	188	Gssctxt *gssctxt;
	189	gss_buffer_desc send_tok,recv_tok;
	190	OM_uint32 maj_status;
	191
	192	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	193	fatal("No authentication or GSSAPI context");
	194
	195	gssctxt=authctxt->methoddata;
	196	recv_tok.value=packet_get_string(&recv_tok.length);
	197
	198	/* Push the error token into GSSAPI to see what it says */
	199	maj_status=PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
	200	&send_tok, NULL));
	201	packet_check_eom();
	202
	203	/* We can't return anything to the client, even if we wanted to */
	204	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	205	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK,NULL);
	206
	207	/* The client will have already moved on to the next auth */
	208
73b00670	209	}
	210
	211	/* This is called when the client thinks we've completed authentication.
	212	* It should only be enabled in the dispatch handler by the function above,
	213	* which only enables it once the GSSAPI exchange is complete.
	214	*/
	215
	216	static void
	217	input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
	218	{
	219	Authctxt *authctxt = ctxt;
	220	Gssctxt *gssctxt;
	221	int authenticated;
	222
	223	if (authctxt == NULL \|\| (authctxt->methoddata == NULL && !use_privsep))
	224	fatal("No authentication or GSSAPI context");
	225
	226	gssctxt=authctxt->methoddata;
	227
	228	/* We don't need to check the status, because the stored credentials
3e196425	229	* which userok uses are only populated once the context init step
	230	* has returned complete.
	231	*/
73b00670	232
	233	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	234
	235	authctxt->postponed = 0;
	236	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
3e196425	237	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
73b00670	238	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
	239	userauth_finish(authctxt, authenticated, "gssapi");
	240	}
	241
	242	static void ssh_gssapi_userauth_error(Gssctxt *ctxt) {
	243	char *errstr;
	244	OM_uint32 maj,min;
	245
	246	errstr=PRIVSEP(ssh_gssapi_last_error(ctxt,&maj,&min));
	247	if (errstr) {
	248	packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERROR);
	249	packet_put_int(maj);
	250	packet_put_int(min);
	251	packet_put_cstring(errstr);
	252	packet_put_cstring("");
	253	packet_send();
	254	packet_write_wait();
	255	xfree(errstr);
	256	}
	257	}
	258
	259	Authmethod method_external = {
	260	"external-keyx",
	261	userauth_external,
	262	&options.gss_authentication
	263	};
	264
	265	Authmethod method_gssapi = {
	266	"gssapi",
	267	userauth_gssapi,
	268	&options.gss_authentication
	269	};
	270
	271	#endif /* GSSAPI */